Infusion packets

ABSTRACT

The present invention relates to an expandable infusion packet (1, 5), wherein the infusion packet is in a permanently compressed state in the absence of water and converts to an expanded state in the presence of water.

FIELD OF THE INVENTION

The present invention relates to infusion packets. More particularly,the present invention is directed towards infusion packets (such as teabags) which expand to adopt a three-dimensional shape upon immersion inwater.

BACKGROUND OF THE INVENTION

For many years infusion packets (for instance tea bags) were typicallyflat and available primarily as square or round sheets of porous filtermaterial with infusible material (for instance tea leaves) sandwichedbetween the sheets. Such packets restrict the movement of the infusiblematerial within the infusion packets to substantially two dimensions. Asa result the infusion performance of such packets is limited.

More recently, mass-produced infusion packets having a morethree-dimensional state have been developed. Of particular success havebeen the tetrahedral-shaped packets such as those whose production isdescribed in WO 95/01907 (Unilever). This type of infusion packet isthought to improve infusion performance by allowing the infusiblematerial more room to move.

Multiple infusion packets are usually packaged together in cartons forsale. For example, PG Tips pyramid tea bags are sold in cartonscontaining 20, 40, 80, 160 or 240 tea bags. A drawback of providingthree-dimensional infusion packets is that they have a larger volumethan two dimensional packets and consequently cannot be packaged forsale as efficiently.

Efforts have been made to provide three-dimensional infusion packetsthat have a flattened configuration for packing.

EP 0 053 204 (Unilever) discloses a tea bag with a generally tetrahedralshape that has at least one fold permitting its collapse to a flattenedconfiguration. A pull means affixed to the bag facilitates unfolding ofthe bag.

WO 2013/174710 (Unilever) discloses an infusion packet comprising agusset which is substantially flat prior to use, and can swell uponimmersion in an infusion liquid such that it adopts a morethree-dimensional shape.

EP 0 846 632 (Fuso Sangyo Kabushiki Kaisha) discloses a liquid-permeableflexible bag body that is folded so that it can easily be accommodatedin an external pack, and unfolded at the time of extraction so that thebag body has its internal space enlarged.

The flattened (or unexpanded) format of such infusion packets isachieved by folding of the three-dimensional infusion packets in adefined manner. The three-dimensional shape that the infusion packetsare intended to adopt when in use will inevitably influence the shape oftheir flattened format. Moreover, in order to facilitate mass-productionof such infusion packets, the flattened format must be achievable via arelatively simple folding pattern. Thus the expandable infusion packetsdescribed in the prior art only have a very limited number of possibleconfigurations in their unexpanded format.

Therefore, there remains scope to provide an infusion packet formatwhich provides the infusion performance associated withthree-dimensional packets and which can be packaged for sale in a moreconvenient and/or efficient manner than is currently the case.

SUMMARY OF THE INVENTION

In a first aspect, the present invention relates to an expandableinfusion packet, wherein the infusion packet is in a permanentlycompressed state in the absence of water and converts to an expandedstate in the presence of water.

The compressed nature of such infusion packets means that they can beconveniently and efficiently packed. This is advantageous from anenvironmental perspective, since less secondary packaging material isneeded to package a given number of infusion packets (e.g. when comparedto standard infusion packets having essentially the same expandedstate).

In a second aspect, the present invention relates to a packagecomprising a plurality of expandable infusion packets according to thefirst aspect of the invention.

In a third aspect, the present invention relates to a method ofmanufacturing an expandable infusion packet according to the firstaspect of the invention.

In a fourth aspect, the present invention relates to an expandableinfusion packet according to the first aspect of the inventionobtainable by the method of the third aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an expandable infusion packet, whereinthe infusion packet is in a permanently compressed state in the absenceof water and converts to an expanded state in the presence of water.

As used herein, the term “permanently compressed state” refers to aformat which is intended to remain stable for an indefinite period oftime. The format of the infusion packet in itself is permanentlycompressed, and does not convert to an expanded state in the absence ofwater. In other words, the infusion packet of the present invention doesnot rely on an envelope or similar secondary packaging to maintain itscompressed format.

When the infusion packets of the present invention are in theirpermanently compressed state, they cannot be unfolded simply by gentlypulling or handling their constituent material. This is in contrast toinfusion packets which have been folded to achieve a flattened format,which readily adopt a more expanded format on being treated in thismanner, even in the absence of water.

The infusion packet of the present invention converts to an expandedstate in the presence of water. Both hot and cold water will elicit thisconversion, although (all other parameters being equal) the time takenfor the infusion packet to adopt the expanded state will usually bequicker in hot water than it is in cold water. As such, the expandableinfusion packet is suitable for preparing both hot and cold beverages.

When the infusion packets of the present invention are in theirpermanently compressed state they do not deform when handled andpreferably have a substantially rigid structure. When they adopt theirexpanded state in the presence of water, they become deformable andpreferably have a flexible structure (in other words they lose therigidity they preferably possess in their permanently compressed state).

The time taken for the infusion packet to convert from the compressed tothe expanded state in the presence of hot water (e.g. at a temperatureof 90 to 100° C.) is typically relatively rapid, and will usually be amatter of seconds. Thus the expandable infusion packet is particularlysuitable for brewing beverages which are prepared with hot water, forinstance tea or herbal infusions. Consumers want to prepare suchbeverages as quickly and conveniently as possible, and the total brewingtime is usually no more than 6 minutes. Thus, in the presence of hotwater, the infusion packet preferably converts from the compressed tothe expanded state in a time of no more than 30 seconds, more preferablyno more than 20, most preferably no more than 10 seconds.

The expandable infusion packets are also appropriate for brewingbeverages which are prepared with cold water (e.g. iced tea brewed fromLipton® Cold Brew tea bags). The brewing time for such beverages istypically longer than for hot beverages, for example it may be 5 minutesor longer. Therefore, rapid conversion of the infusion packet from thecompressed to the expanded state is less important as far as consumeracceptance of the product is concerned. In the presence of cold water(e.g. at a temperature of 15 to 25° C.) the infusion packet preferablyconverts from the compressed to the expanded state in a time of no morethan 240 seconds, more preferably no more than 180 seconds, still morepreferably no more than 120 seconds and most preferably no more than 90seconds.

The conversion of the expandable infusion packet from the permanentlycompressed state to the expanded state results in a “tumbling” motion.Without wishing to be bound by theory, the inventor believes that thismotion improves the infusion performance of the infusion packet.

The expandable infusion packets preferably contain a beverage precursor.As used herein the term “beverage precursor” refers to a fabricatedcomposition suitable for preparing a beverage. The beverage precursormay be contacted with an aqueous liquid such as water to provide abeverage (i.e. a substantially aqueous drinkable composition which issuitable for human consumption). This process is referred to as brewing.During brewing the beverage precursor typically releases certain solublesubstances into the aqueous liquid, e.g. flavour and/or aroma molecules.

The beverage precursor preferably comprises plant material, with teaand/or herb plant material being particularly preferred. As used herein“tea plant material” refers to dried leaf and/or stem material derivedfrom Camellia sinensis (i.e. “leaf tea”). The term “herb plant material”refers to material which is commonly used as a precursor for herbalinfusions. Preferably the herb plant material is selected fromchamomile, cinnamon, elderflower, ginger, hibiscus, jasmine, lavender,lemongrass, mint, rooibos, rosehip, vanilla and verbena. The beverageprecursor may additionally or alternatively comprise fruit pieces (e.g.apple, blackcurrant, mango, peach, pineapple, raspberry, strawberry,etc.) and/or other flavor ingredients (e.g. bergamot, citrus peel,synthetic flavor granules, and the like). The beverage precursorpreferably excludes plant material which requires pressure for optimumbrewing. In particular, the beverage precursor preferably excludes plantmaterial derived from coffee (especially ground coffee).

It is preferred that the mass of the beverage precursor is at least 1 g,as smaller amounts are difficult to accurately portion and dose. Morepreferably the mass is at least 1.2 g, and most preferably at least 1.4g. It is further preferred that the mass of the beverage precursor isless than 4 g, as larger amounts become inconvenient to store and/orhandle. More preferably the mass is less than 3.5 g, and most preferablyless than 3 g.

The expandable infusion packet preferably has a first geometric shape inits permanently compressed state and a second geometric shape in itsexpanded state. Although it is possible for the second geometric shapeto be an expanded version of the first geometric shape, it is preferredthat the first and second geometric shapes are distinct. In other words,the infusion packet preferably has a particular geometric shape in thepermanently compressed state, and converts to the expanded state whereinit adopts a different geometric shape.

For example, the infusion packet could have an essentially disc-shaped,cylindrical conformation in the compressed state (i.e. the firstgeometric shape is a cylinder), and then, on the addition of water,convert so as to have an essentially tetrahedral conformation in theexpanded state (i.e. the second geometric shape is a tetrahedron).

The first geometric shape preferably has a first face and a second faceconnected along a length (L), wherein the cross-section along the length(L) is constant, and is the same shape as the first and second faces.The first and second face are preferably parallel to one another.

It is preferred that the first geometric shape is a cylinder or a prism.

Where the first geometric shape is a cylinder, the first face and thesecond face are circular or elliptical, and are connected along thelength (L) by a curved surface.

When the first geometric shape is a prism, the first face and the secondface are polygonal and are connected along the length (L) by a pluralityof joining faces, which are delimited from one another by a plurality ofjoining edges. The joining faces are preferably square or rectangular(i.e. the prism is preferably a right prism). Nevertheless, it will beappreciated that in a less preferred configuration the joining facescould be parallelograms (i.e. the prism could be an oblique prism).

The first and second faces can have any simple polygonal shape (i.e. ashape wherein the boundary of the polygon does not cross itself); assuch the polygonal shape can be concave or convex. Non-limiting examplesof suitable polygonal shapes include: triangles, quadrilaterals,pentagons, hexagons, heptagons, octagons, nonagons, decagons, or thelike.

The geometry and dimensions of the infusion packet in its permanentlycompressed state will determine how efficiently a plurality of suchpackets can be packaged.

The first geometric shape preferably has a width (W), wherein the width(W) is greater than or equal to the length (L).

The width (W) is the widest dimension of the first or second face in aplane which is perpendicular to the length (L). For example, for acylinder with a circular cross-section, the width (W) is the diameter ofthe circular cross-section, whilst for a cylinder with an ellipticalcross-section, the width (W) represents the major axis of the ellipticalcross-section. Similarly, for a prism with a square cross-section, thewidth (W) represents the diagonal of the square cross-section.

The length (L) of the cylindrical or prismatic infusion packet in thepermanently compressed state is preferably greater than 2 mm, morepreferably greater than 3 mm, and most preferably greater than 4 mm. Thelength (L) is preferably no more than 20 mm, more preferably no morethan 18 mm, and most preferably no more than 16 mm.

The width (W) of the cylindrical or prismatic infusion packet in thepermanently compressed state is preferably greater than 14 mm, morepreferably greater than 17 mm, and most preferably greater than 20 mm.The width (W) is preferably no more than 45 mm, more preferably no morethan 40 mm, and most preferably no more than 35 mm.

The expandable infusion packet preferably has a second geometric shapein its expanded state. As set out above, this second geometric shape ispreferably a different shape to the first geometric shape.

An embodiment wherein the second geometric shape is essentially flat(e.g. an infusion packet comprising infusible material sandwichedbetween square or round sheets of porous material) is not precluded.However, such an embodiment is less preferred, since infusion packets ofthis type are believed to restrict the movement of the infusiblematerial to substantially two dimensions, thereby limiting theirinfusion performance. Furthermore, packaging a plurality of this type ofinfusion packets is already relatively efficient due to theiressentially flat nature.

Thus it is preferred that the second geometric shape is athree-dimensional shape. There is no particular limitation with regardto the second geometric shape, and it can be any three-dimensionalshape. However, it is desirable that infusion packets having the secondgeometric shape can be readily manufactured on a large-scale. Thuspreferred examples of the second geometric shape include shapes such astetrahedral, pyramidal, hemispherical, spherical, cubic, and the like.It is particularly preferred that the second geometric shape is asphere, a hemisphere, a tetrahedron or a pyramid.

The present invention envisages compressing conventional infusionpackets so as to achieve a format wherein the infusion packets are in apermanently compressed state. Non-limiting examples of conventionalinfusion packets include spherical or hemispherical infusion packetssuch as those described in EP 0811562 (Unilever), WO 2012/095247(Unilever) or WO 2005/051797 (Tetley), and tetrahedral-shaped infusionpackets such as those described in WO 95/01907 (Unilever), WO2004/033303 (I.M.A. SPA), or WO 2012/004169 (Unilever).

The expandable infusion packet preferably has a first geometric shape inits permanently compressed state and a second geometric shape in itsexpanded state. Although it is possible for the second geometric shapeto be an expanded version of the first geometric shape, it is preferredthat the first and second geometric shapes are distinct. In other words,the infusion packet preferably has a particular geometric shape in thepermanently compressed state, and converts to the expanded state whereinit has a different geometric shape.

The expandable infusion packet has a volume V_(C) in the permanentlycompressed state and a volume V_(E) in the expanded state. In orderachieve a significant reduction in the packaging space occupied by eachcompressed infusion packet without impacting infusion performance, asignificant increase in volume occurs when the infusion packet convertsfrom its permanently compressed state to its expanded state on theaddition of water. Thus, V_(E) is preferably at least 2V_(C), morepreferably at least 2.5V_(C), and most preferably at least 3V_(C). Theexpandable infusion packet should be able to convert from itspermanently compressed state to its expanded state in an efficientmanner on the addition of water. Thus V_(E) is preferably no more than10V_(C), more preferably no more than 8V_(C), and most preferably nomore than 6V_(C).

The expandable infusion packet of the present invention can be made fromany suitable material. Non-woven materials are particularly preferred,since these materials typically have relatively little “memory” in thefibres, and therefore readily convert from the compressed state to theexpanded state on the addition of water. Non-limiting examples ofnon-woven materials include non-woven materials made with continuousfilaments (e.g. PET, PLA, PP) and wet laid non-woven materials (e.g.cellulose/polymer blends comprising cellulose and polymers such as PP,PE, or PLA).

In a second aspect, the invention relates to a package comprising aplurality of expandable infusion packets according to the first aspectof the invention.

As mentioned above, the geometry of the expandable infusion packet inits permanently compressed state will determine how efficiently aplurality of such packets can be packaged. Nevertheless, the infusionpackets of the present invention will require less storage space intheir compressed state than in their expanded state, regardless of theparticular geometry chosen.

The format of the package is not limited. For cost reasons, it ispreferred that the package chosen is not overly complicated tomanufacture. From the standpoint of simplicity, it is preferred that thepackage is a tube or a carton. A further benefit of such packagingsolutions is that the packaged product only requires a small amount ofstorage space in the consumer's home. Indeed, it is preferred that thesecondary packaging is sufficiently compact that the infusion packetscan be conveniently carried around by the consumer or kept at work.

Examples of such tubular packages include cardboard, plastic, ormetallic tubes having an appropriately shaped cross-section. Forexample, if the expandable infusion packet has a triangularcross-section in the compressed shape, a hollow tube having a triangularcross-section could efficiently package a plurality of such infusionpackets. It is also envisaged that the tubular package could be formedaround the compressed infusion packets. For example, a plurality ofcompressed infusion packets could be arranged in a stack, and packagedin a tubular manner by way of a sheet of flexible packaging material(e.g. paper or plastic) being wrapped around the stacked infusionpackets in a circumferential manner and sealed where the edges of thesheet meet (i.e. in a longitudinal direction such that the seal isessentially parallel to the length (L) of the compressed infusionpackets).

In one preferred embodiment, the package is a tube and the firstgeometric shape is a cylinder (i.e. the expandable infusion packet hasan essentially disc-shaped, cylindrical conformation in the permanentlycompressed state).

The tube does not need to have the same cross-section as the expandableinfusion packet. Thus, in embodiments wherein the package is a tube andthe first geometric shape is a cylinder, the tube may have a circular orelliptical cross-section and hence match the cross-section of the firstgeometric shape.

Alternatively, the tube may have a cross-section which does not matchthat of the first geometric shape. The space between the infusion packetand the tube in such an embodiment is believed to facilitate removal ofthe infusion packet from the carton (by allowing the consumer to easilygrip the curved surface of the infusion packet). A tube with a square orrectangular cross-section is particularly preferred, since such cartonsare easily manufactured.

It will be appreciated that a similar effect can be achieved with othershapes of infusion packets. For example, an expandable infusion packetwherein the first geometric shape is a hexagonal prism could be packagedin a tube having a square cross-section, etc.

As set out above, the secondary packaging can be a carton. The tubularformat described above relates to a packaging solution for a stack ofcompressed infusion packets. In contrast, a carton provides a solutionfor packaging layers or rows of the compressed infusion packets (whereineach layer or row comprises two or more compressed infusion packets). Itis possible to package compressed infusion packets in this mannerregardless of the first geometric shape of such infusion packets. Formaximum packaging efficiency, it is preferred that the first geometricshape tessalates. Nevertheless, this is not an essential requirement,and non-tessalating shapes will also be packaged more efficiently thatconventional non-compressed infusion packets. Furthermore, the spacebetween rows of compressed infusion packets having non-tessalatingshapes may facilitate convenient removal of the individual infusionpackets from the carton by the consumer.

In a preferred embodiment, the package is a carton and the firstgeometric shape is a square or rectangular prism (i.e. the expandableinfusion packet has a prismatic conformation with a square orrectangular cross-section in the permanently compressed state).

In a further preferred embodiment, the package is a carton and the firstgeometric shape is a cylinder (i.e. the expandable infusion packet hasan essentially disc-shapes, cylindrical conformation in the permanentlycompressed state). A carton with a square or rectangular cross-sectionis particularly preferred, since such cartons are easily manufactured.The space between the rows of infusion packets and the carton isbelieved to facilitate removal of the infusion packet from the carton(by allowing the consumer to easily grip the curved surface of theinfusion packet).

In a third aspect, the present invention relates to a method ofmanufacturing an expandable infusion packet according to the firstaspect of the invention.

In particular, the invention relates to a method comprising thefollowing steps:

-   (a) providing an infusion packet in an expanded state;-   (b) inserting the infusion packet in a die;-   (c) applying pressure so as to convert the infusion packet to a    permanently compressed state.

As already discussed, the present invention envisages compressingconventional infusion packets so as to achieve a format wherein theinfusion packets are in a permanently compressed state. Thus theinfusion packet provided in step (a) is preferably a conventionalinfusion packet, and can be manufactured by any known method.Tetrahedral-shaped infusion packets are particularly preferred.

The infusion packet provided in step (a) is inserted into a die. It ispreferred the die is metallic, for example it can conveniently be madeof steel.

The pressure applied in step (c) is preferably from 3000 to 4200 kPa,more preferably from 3100 to 4100 kPa. Factors which influence theappropriate pressure include the type of material the infusion packet ismade from and the size/weight of the infusion packet. The pressureapplied in step (c) will typically be higher where a greater degree ofcompression is desired, and lower where a smaller degree of compressionis desired.

The pressure is preferably applied via a piston which fits into the die.It is preferred that the piston is metallic, for example it canconveniently be made of aluminium. The die and the piston are preferablymade from different metals.

It will be appreciated that the amount of infusible material containedwithin the infusion packet has a given volume (e.g. the volume occupiedby 3 g of infusible material will be greater than that occupied by 2 gof infusible material). As a general rule, the more infusible materialcontained within the infusion packet, the greater the volume occupied bythat infusible material. As such, infusion packets comprising higheramounts of infusible material will typically be compressed to a lesserdegree than infusion packets comprising lower amounts of infusiblematerial.

In a further aspect, the present invention relates to an expandableinfusion packet according to the first aspect of the invention whereinthe expandable infusion packet is obtainable by the method of the thirdaspect of the invention. In other words, an expandable infusion packet,wherein the infusion packet is in a permanently compressed state in theabsence of water and converts to an expanded state in the presence ofwater, the expandable infusion packet being obtainable by a processcomprising the steps of: (a) providing an infusion packet in an expandedstate; (b) inserting the infusion packet in a die; (c) applying pressureso as to convert the infusion packet to a permanently compressed state.

FIGURES

By way of example, the present invention is illustrated with referenceto the following figures, in which:

FIG. 1a is a perspective view of an expandable infusion packet in apermanently compressed state;

FIG. 1b is a perspective view of the expandable infusion packet of FIG.1a in an expanded state;

FIG. 2a is a perspective view of a compressed infusion packet accordingto the invention which has been placed in a receptacle ready forbrewing;

FIG. 2b is a representation of the infusion packet of FIG. 2a once waterhas been added to the receptacle so as to prepare a beverage;

FIG. 3a is a perspective view showing an arrangement of a plurality ofcompressed infusion packets;

FIG. 3b is a perspective view showing one embodiment of a packagecomprising a plurality of compressed infusion packets;

FIG. 3c is a perspective view showing an alternative embodiment of apackage comprising a plurality of compressed infusion packets;

FIG. 4 shows a series of perspective views illustrating possible shapesfor expandable infusion bags according to the present invention in theirpermanently compressed state.

FIG. 5a is a perspective view of an infusion packet with a hemisphericalexpanded state;

FIG. 5b is a perspective view of an infusion packet with a cubicexpanded state;

FIG. 6 is a perspective view showing a carton comprising a plurality ofcompressed infusion packets;

FIG. 7 illustrates different arrangements a plurality of compressedinfusion packets;

FIG. 8 is a perspective view showing a carton comprising a plurality ofcompressed infusion packets.

FIG. 1a shows an expandable infusion packet according to the inventionin its permanently compressed state. The compressed infusion packet (1)is cylindrical and has a circular cross-section. In this format, theinfusion packet has a circular first face (2) and circular second face(which is opposite the first face, and thus not visible in FIG. 1a )connected along a length (L) by a curved surface (4). The cross-sectionalong the length (L) is constant, and is the same shape as the first andsecond faces (i.e. circular). In the illustrated embodiment, the width(W) is the diameter of the circular cross-section.

FIG. 1b shows the infusion packet of FIG. 1a in its expanded state. Theexpanded infusion packet (5) has adopted a three-dimensional tetrahedralshape. As such, the infusion packet has a different shape in itsexpanded state than it had in its compressed state. Thethree-dimensional expanded state allows the infusible material (6) roomto move within the infusion packet (5), which is believed to improveinfusion performance.

FIG. 2 illustrates the conversion of an expandable infusion packetaccording to the present invention from its permanently compressed stateto its expanded state. This conversion occurs under the conditionstypically used by a consumer to prepare an infusion from a conventionalinfusion packet.

FIG. 2a shows the infusion packet prior to the start of brewing. Thecompressed infusion packet (1) has been placed in a receptacle (7) whichis suitable for receiving a quantity of hot water (in this case a mug).In order to prepare a beverage from the compressed infusion packet theconsumer adds hot water to the receptacle. The infusion packet convertsto an expanded state in the presence of water (8). The volume of waterused by consumers to prepare a beverage from a conventional infusionpacket varies, and is not constant from one geography to another. Thus,it is preferably that the volume of water that will cause the infusionpacket to convert from its permanently compressed state to its expandedstate is not very large, although it will be appreciated that thisvolume is typically greater than V_(E) (100 ml of water will usually besufficient). FIG. 2b shows the infusion packet during brewing. Theinfusion packet is now in its expanded state (5), and has adopted athree-dimensional tetrahedral shape.

As shown by FIG. 3, the compressed infusion packets of the presentinvention can be conveniently packaged.

FIG. 3a shows a plurality of compressed infusion packets (1), which havebeen stacked one on top of the other. Since the infusion packets have aregular shape in the compressed state, this arrangement results in aformat with a constant cross-section (in this case, a circularcross-section).

FIG. 3b shows a possible way of packaging a plurality of compressedinfusion packets (1). The stack of expandable infusion packets is kepttogether by secondary packaging (9). In FIG. 3b this secondary packaging(9) is tubular and takes the form of a sheet (e.g. formed of paper orplastic) which extends around the infusion packets in a circumferentialmanner and is sealed where its edges meet.

FIG. 3c shows an alternative way of packaging a plurality of compressedinfusion packets (1). In FIG. 3c the secondary packaging (9) is acardboard tube having a square cross-section. This carton has the formof a square prism. Although the compressed infusion packets do not fillthe entire volume of the carton, the packaging efficiency is stillimproved (i.e. a carton designed to accommodate an equivalent number ofconventional infusion packets having an expanded format would have asignificantly larger volume).

Although not illustrated, it will be appreciated that yet more secondarypackaging formats are possible (e.g. a cardboard or plastic tube, etc.).

The shape of the expandable infusion packet in its permanentlycompressed state may be prismatic. FIG. 4 shows some possible prismaticconfigurations.

In FIG. 4a the compressed infusion packet has the form of a triangularprism. In this format, the first and second faces of the infusion packetare triangular, and are connected along the length (L) by threerectangular joining faces (11), which are delimited from one another bythree joining edges (12). In this embodiment, the width (W) is thedistance between two adjacent vertices of the triangular cross-section.

In FIG. 4b the compressed infusion packet is a square prism. In thisformat, the first and second faces of the infusion packet are square,and are connected along the length (L) by four rectangular joining faces(11), which are delimited from one another by four joining edges (12).In this embodiment, the width (W) is the diagonal of the squarecross-section.

FIGS. 4c and 4d illustrate two possible hexagonal prism configurationsfor the compressed infusion packet. In both instances, the first andsecond faces of the infusion packet are hexagonal, and are connectedalong the length (L) by six rectangular joining faces (11), which aredelimited from one another by six joining edges (12). The compressedinfusion packet of FIG. 4c has a convex hexagonal cross-section, whereasthe compressed infusion packet of 4 d has an L-shaped concave hexagonalcross-section.

The shape of the expandable infusion packet in its expanded state is notlimited, and can be any geometric shape. FIG. 5 shows some possibleconfigurations.

In FIG. 5a the expanded infusion packet (5) has a three-dimensionalhemispherical shape, whilst in FIG. 5b it has a cubic shape in itsexpanded form.

It will be appreciated that there is no particular link between theshape of the expandable infusion packet in its compressed state and inits expanded shape. In particular, an infusion packet having any one ofthe expanded shapes shown in FIGS. 1b, 5a and 5b can be compressed so asto have any one of the configurations shown in FIGS. 1a, 4a, 4b, 4c and4 d.

The shape of the infusion packet in its compressed state could be usedas a code help consumers identify the appropriate product. For example,a range of products are often sold by a particular manufacturer (such asgreen tea, black tea, fruit and herbal infusions, etc.). Conventionally,each member of the range uses the same shaped infusion packet (e.g.tetrahedral). Each type of product is sold in a separate package (e.g. acarton containing a certain number of infusion packets), and theinformation provided on the package identifies the particular producttype. The present invention allows each product in the range to have adifferent shape in the permanently compressed state (whilst stillmaintaining a common shape in the expanded state). For example, infusionpackets containing black tea could have the form of a cylinder, whilstthose containing green tea could have the form of a hexagonal prism, andso on. In this way, even if the compressed infusion packets had beenremoved from the package in which they were sold, the consumer wouldstill be able to visually identify each product in the range.

FIG. 6 shows a possible way of packaging a plurality of compressedinfusion packets. In this Figure, a number of compressed infusionpackets (1) are arranged inside a cardboard carton (15). The squarecross-section of the infusion packets (1) means that they tessalate,thus resulting in a very efficient use of the internal space within thecarton.

FIG. 7 illustrates different arrangements a plurality of compressedinfusion packets. FIG. 7a shows a plurality of compressed infusionpackets (1) having a hexagonal cross-section which have been stacked oneon top of the other. The regular shape of these infusion packets in thecompressed state means that the stack of infusion packets has a constantcross-section. The stack of expandable infusion packets can be packagedso as to maintain this arrangement (e.g. in a similar manner to thatillustrated for in FIG. 3b ).

FIG. 7b shows an alternative arrangement of compressed infusion packets(1) having a hexagonal cross-section. In this arrangement, thecompressed infusion packets are arranged in a single layer. The regularhexagonal cross-section of the infusion packets (1) means that theytessalate. The layer of expandable infusion packets can be packaged soas to maintain this arrangement (e.g. by packaging them in a cardboardcarton).

FIG. 8 shows a possible way of packaging a plurality of compressedinfusion packets. In this Figure, a number of compressed infusionpackets (1) are arranged inside a cardboard carton (15). The circularcross-section of the infusion packets (1) means that they do nottessalate. Nevertheless, the compressed infusion packets are still veryefficiently packaged, whilst the small amount of space around thecompressed infusion packets allows the consumer to easily remove anindividual infusion packet by gripping the curved surface thereof.

Although not illustrated, it will be appreciated that the finalpackaging arrangement could comprise multiple layers of the compressedinfusion packets. Indeed, it is also envisaged that each layer ofinfusion packets could have a different shape in the compressed format.For example, a first layer could consist of infusion packets having ahexagonal cross-section, with a second layer consisting of infusionpackets having a square cross-section.

Examples

A commercially available PG Tips pyramid tea bag (bag weight ˜2.9 g) wasprovided. The shape of this tea bag in the expanded state wasessentially tetrahedral (edge length ˜65 mm). The volume of the tea bagin the expanded state (V_(E)) was ˜32365 mm³.

The tea bag was inserted into a steel die having the form of a hollowcylinder and converted into a permanently compressed state by applying500 psi (3447 kPa) pressure via an aluminium piston that slides withinthe cylindrical die thereby compressing the tea bag. The shape of thistea bag in the permanently compressed state was essentially cylindrical(with a circular cross-section). The width (W) of the compressedcylindrical format of the tea bag was ˜34 mm, and the length (L) was˜7.5 mm. The volume of the tea bag in the permanently compressed state(V_(C)) was ˜6809 mm³.

The permanently compressed tea bag was placed in an empty cup, and 200ml of hot water was added. The tea bag converted to its expanded form ina matter of seconds. Moreover, this conversion caused the tea bag to“tumble”. This movement facilitates rapid brewing of the tea leavescontained within the tea bag without the need for stirring or otherwiseagitating the tea bag.

For comparison, a non-compressed, commercially available PG Tips pyramidtea bag (bag weight ˜2.9 g) was placed in an empty cup, and 200 ml ofhot water was added. The addition of the water caused temporaryflattening of the tea bag. Furthermore, although the tea bag floatedonce addition of the water was completed, it did not “tumble” and wasessentially static during brewing. The lack of movement meant that thetea leaves contained within the tea bag did not brew as rapidly.

1. Expandable infusion packet, wherein the infusion packet is in apermanently compressed state in the absence of water and converts to anexpanded state in the presence of water, and wherein the infusion packethas a substantially rigid structure in the permanently compressed state.2. Expandable infusion packet as claimed in claim 1 wherein the infusionpacket has a volume Vein the permanently compressed state and a volumeV_(E) in the expanded state and wherein V_(E) is from 2V_(C) to 10V_(C).3. Expandable infusion packet as claimed claim 1 wherein the infusionpacket has a first geometric shape in its permanently compressed stateand a second geometric shape in its expanded state, wherein the firstand second geometric shapes are distinct.
 4. Expandable infusion packetas claimed in claim 3 wherein the first geometric shape is a cylinder.5. Expandable infusion packet at claimed in claim 3 wherein firstgeometric shape is a prism.
 6. Expandable infusion packet as claimed inclaim 1 wherein the second geometric shape is a sphere, a hemisphere, atetrahedron or a pyramid.
 7. Expandable infusion packet as claimed inclaim 1 wherein the infusion packet is made from a non-woven material.8. A package comprising a plurality of expandable infusion packets asclaimed in claim
 1. 9. A package as claimed in claim 8 wherein thepackage is a tube or a carton.
 10. A package as claimed in claim 9wherein the package is a tube and the first geometric shape is acylinder.
 11. A package as claimed in claim 9 wherein the package is acarton and the first geometric shape is a square or rectangular prism.12. A package as claimed in claim 9 wherein the package is a carton andthe first geometric shape is a cylinder.
 13. A method of manufacturingan expandable infusion packet as claimed in claim 1, the methodcomprising: (a) providing an infusion packet in an expanded state; (b)inserting the infusion packet in a die; (c) applying pressure so as toconvert the infusion packet to a permanently compressed state, whereinthe infusion packet has a substantially rigid structure in thepermanently compressed state.
 14. A method as claimed in claim 13wherein the pressure applied in step (c) is from 3000 to 4200 kPa. 15.(canceled)